Chest
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Pulmonary hypertension causes right ventricular ischemia and failure as a result of increased afterload combined with reduced coronary blood flow. Increasing coronary driving pressure by raising aortic pressure with phenylephrine has been shown to reverse right ventricular ischemia from pulmonary hypertension in animals. Since vasodilators often fail to reduce afterload, we tested whether raising the coronary driving pressure would improve right ventricular function in man. ⋯ Although phenylephrine increased right ventricular coronary driving pressure, it worsened right ventricular function as manifest by a rise in end-diastolic pressure and fall in cardiac output. Any benefit of raising right ventricular coronary driving pressure may have been offset by alpha vasoconstriction of right ventricular coronary blood flow and/or pulmonary arterial vasoconstriction. Phenylephrine does not appear to be a useful therapy of right ventricular failure from pulmonary hypertension in patients who fail vasodilators.
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Marfan syndrome is a hereditable disorder of connective tissue that causes several distinct cardiovascular abnormalities, including aortic regurgitation, dissection, and aneurysm. These cardiac manifestations can be identified with echocardiography, computer tomography, and angiography. ⋯ This patient with Marfan syndrome whose case is reported herein presented with chest pain, hypertensive crisis, and aortic insufficiency; labetalol was used successfully to treat the acute hypertensive crisis and magnetic resonance imaging (MRI) was used to differentiate between aortic dissection and an expanding aortic aneurysm. This report is unique in that labetalol was used to control the hypertensive crisis in Marfan syndrome and MRI was used as the initial diagnostic modality in an emergency setting.
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Comparative Study
Three mixed venous saturation catheters in patients with circulatory shock and respiratory failure.
Thirty-one critically ill patients with acute respiratory failure and circulatory shock were divided into three groups. Group 1 included 11 patients with an inserted mixed venous saturation (SvO2) catheter using three-reference wavelengths and characterized by one transmitting and one detecting fiberoptic filament (Oximetrix opticath catheter); group 2 included eight patients with an inserted SvO2 catheter using two-reference wavelengths and characterized by one transmitting and one detecting fiberoptic filament; (Edwards sat-one catheter); group 3 included 12 patients with an inserted SvO2 catheter using two-reference wavelengths and characterized by one transmitting and two detecting fiberoptic filaments. Once calibration procedures were performed, SvO2 measured by the catheter and by an hemoximeter OSM 3 (reference value) were compared following each therapeutic intervention. ⋯ After 24 hours, the spontaneous drifts in the two-reference wavelength systems, using either one or two detecting fiber optic filaments (expressed as the SvO2 value measured by the catheter minus the reference SvO2 value) were significantly higher than the spontaneous drift in the three-reference wavelength system (9.3 +/- 7 percent for the Edwards catheter and +/- 6 +/- 4.1 percent for the Spectramed catheter vs 3.3 +/- 3.1 percent for the Oximetrix catheter, p less than 0.05). This study shows that a three-wavelength system is more accurate than a two-wavelength system for measuring acute changes in SvO2. The addition of a second detecting fiber optic filament does not seem to improve the accuracy of the system when SvO2 changes occur in conditions of stable hematocrit.
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We report the terms used by 223 pulmonary physicians and 54 physicians in other specialties to describe eight recorded examples of lung sounds. The participants listened to the lung sounds at the 1988 American College of Chest Physicians annual convention and wrote "free form" answers. Pulmonary physicians used the terms "crackles" and "rales" with equal frequency to describe discontinuous adventitious lung sounds (ALS) and not at all to describe continuous ALS. ⋯ The majority of participants recognized the normal breath sounds but not the pleural friction rub. Most did not use a qualifying adjective to describe ALS, and there was little agreement among those who did. The lung sound terminology used by physicians is not well standardized and the recommendations of the ATS/ACCP nomenclature subcommittee are not widely accepted.